Growth in the U.S. cell-only population has sparked growing concern that telephone surveys of the general public in the United States will become increasingly subject to coverage bias. In addition, newer technologies like VOIP and Wi-Fi communications are rapidly changing the landscape of where people can be reached to answer surveys. While bias from excluding the U.S. cell-only population from survey samples has been minimal historically due to the relatively small size of this group and other factors, the experience in some European countries with high cell-only penetration (such as Finland) point to an increasing problem of potential bias in U.S. surveys. Though demographic weighting could be used to eliminate some of that bias, availability of weights that describe the various subpopulations lag behind the rapidly changing cell-only population. Moreover, the absence of data on demographics by communications lifestyle complicates the problem of efficient sample design. However, we propose a reliable model that forecasts cell-only population size and demographics by positing that a stable behavioral process, the rate of habit retention, can be estimated from prior wireless lifestyle adoption in the U.S., which may also describe cell-only lifestyle adoption. Our model uses measures of incentive and habituation to test this assumption by predicting changes in the cell-only population size and age demographics. We then extend the model to address the changing demographic characteristics of the subpopulation that has both cell and landline and the subpopulation that uses only landline telephone service.